System.Data.DataColumn serializes some properties with a default value (different from the .NET Framework)

[rmkarasev]

Environment

Microsoft Visual Studio 2022
Version 17.9.3

.NET version

.NET 6 (we use)
.NET 8

Did this work in a previous version of Visual Studio and/or previous .NET release?

Works in the same Visual Studio 2022 Version 17.9.3 or previous versions, but targeting to .NET Framework 4.8.

Issue description

We have a custom Component and ComponentDesigner those are used to create/populate multiple DataTable and DataColumn in the design-time.

After migrating to .NET 6 we are experiencing with an issue that each DataColumn serialize some properties to .Designer.cs and .resx files that looks needless and just increase file size and noise.

Previous code:

this.dataColumn35.ColumnName = "DischargedDate";
this.dataColumn35.DataType = typeof(System.DateTime);

Current code:

dataColumn35.Caption = "DischargedDate";
dataColumn35.ColumnName = "DischargedDate";
dataColumn35.DataType = typeof(System.DateTime);
dataColumn35.DefaultValue = resources.GetObject("dataColumn35.DefaultValue");
dataColumn35.Namespace = "";

and .resx

  <data name="dataColumn35.DefaultValue" mimetype="application/x-microsoft.net.object.binary.base64">
    <value>
        AAEAAAD/////AQAAAAAAAAAMAgAAAEhTeXN0ZW0uUHJpdmF0ZS5Db3JlTGliLCBDdWx0dXJlPW5ldXRy
        YWwsIFB1YmxpY0tleVRva2VuPTdjZWM4NWQ3YmVhNzc5OGUFAQAAAB9TeXN0ZW0uVW5pdHlTZXJpYWxp
        emF0aW9uSG9sZGVyAwAAAAREYXRhCVVuaXR5VHlwZQxBc3NlbWJseU5hbWUBAAEIAgAAAAoCAAAABgMA
        AAAACw==
</value>
  </data>

So, ton of Caption, DefaultValue, Namespace properties are added when changing the form design in new Windows Forms Designer..

Is this issue already known? How can be this fixed?

Steps to reproduce

Minimal project is attached

DataColumnSerializationIssue.zip

[elachlan]

@Tanya-Solyanik are we serialising some default values on purpose?

[Tanya-Solyanik]

DataColumn.Caption should be serialized on both versions:
https://source.dot.net/#System.Data.Common/System/Data/DataColumn.cs,345
https://referencesource.microsoft.com/#System.Data/fx/src/data/System/Data/DataColumn.cs,371
If it's not set explicitly, column name is used.

DataColumn.Namespace should be serialized on both versions too:
https://source.dot.net/#System.Data.Common/System/Data/DataColumn.cs,987
https://referencesource.microsoft.com/#System.Data/fx/src/data/System/Data/DataColumn.cs,1002
It seems that in NET6 version of the app _columnUri is not null.

DataColumn.DefaultValue should be serialized as a string using the converter -
https://source.dot.net/#System.Data.Common/System/Data/DataColumn.cs,640
https://source.dot.net/#System.Data.Common/System/Data/DefaultValueTypeConverter.cs,3060fb00499d852e
https://source.dot.net/#System.Data.Common/System/Data/DataColumn.cs,1750
https://referencesource.microsoft.com/#System.Data/fx/src/data/System/Data/DataColumn.cs,1725

So far this looks like designer bug. @Olina-Zhang - could you please copy it to the designer repo?

[Philip-Wang01]

@Tanya-Solyanik Filed a DT issue: https://github.com/microsoft/winforms-designer/issues/5964 to track it.